1. Field of the Disclosure
The present disclosure relates generally to decontamination and/or cleaning, and more specifically to decontamination and/or cleaning of fragile materials, for example certain historic artifacts.
2. Background Information
Decontamination and/or cleaning of materials typically involves the application of a solvent along with substantial mechanical energy, for example, mechanical energy in the form of shear caused by a high pressure spray, a stirred or ultrasonic bath, mechanical scrubbing, or other techniques. The application of mechanical energy generally causes the removal of contaminates by convective mass transfer.
However, many conventional decontamination and/or cleaning techniques are unsuited for cleaning fragile materials, for example, delicate historic artifacts such as textiles, skins, papers, and other frail items. These types of historic artifacts are often mechanically fragile, and thus respond adversely to high pressure spraying, stirred or ultrasonic baths, mechanical scrubbing and other aggressive techniques. Similarly, such historic artifacts are often incompatible with many solvents, as the solvents may remove, in addition to the undesired contaminates, desired pigments, dyes, inks, paints, stains, and/or other types of substances present on the artifact. Due to the typically high monetary and cultural value of historic artifacts, even very minor damage due to decontamination and/or cleaning is generally deemed unacceptable.
Yet the need to decontaminate and/or clean fragile materials, such as delicate historic artifacts, still exists despite the challenges the process presents. In addition to cleaning rather innocuous contaminates from artifacts for largely aesthetic reasons, decontamination and/or cleaning may be needed to remove toxic contaminates that are potentially harmful to people handling the artifacts. Some historic artifacts are contaminated from the environment in which they were discovered or historically maintained. More often, historic artifacts have been unintentionally contaminated by museum personnel or others, who applied toxic chemicals to the artifacts in preservation efforts.
In the nineteenth and early twentieth century many historic artifacts in museum collections were treated with a variety of pesticide, fungicides, and other preservative agents. For example, during the ninetieth and early twentieth centuries tobacco, camphor, strychnine, carbolic acid, sulfur, mercuric chloride, thymol, naphthalene, and several forms of arsenic were often used for preservation. In the later half of the twentieth century other types of chemicals were often used, including various organochlorides (such as DDT and lindane), organophosphates (such as malathion), and organometallic compounds (such as methyl mercury acetate and or triethyl arsine). These chemicals were often liberally brushed, sprayed, and/or sprinkled onto the surfaces of the historic artifacts. Despite the passage of time, many historic artifacts in museum collections are still highly contaminated with toxic residues from these chemicals. Prolonged exposure to the artifacts may cause any of a variety of maladies to exposed persons. This hazard hinders the work of museum personnel and researchers, who need to handle the artifacts to create exhibits or to study the artifacts. Similarly, this hazard inhibits the return of some historic artifacts to native peoples who may have legal rights to the artifacts.
Accordingly, there is a need for techniques to decontaminate and/or clean fragile materials, such as delicate historic artifacts, that address their special needs, while effectively decontaminating and/or cleaning the materials.